diff options
Diffstat (limited to 'lib/select.c')
| -rw-r--r-- | lib/select.c | 529 |
1 files changed, 529 insertions, 0 deletions
diff --git a/lib/select.c b/lib/select.c new file mode 100644 index 000000000..32b6fa55f --- /dev/null +++ b/lib/select.c @@ -0,0 +1,529 @@ +/*************************************************************************** + * _ _ ____ _ + * Project ___| | | | _ \| | + * / __| | | | |_) | | + * | (__| |_| | _ <| |___ + * \___|\___/|_| \_\_____| + * + * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al. + * + * This software is licensed as described in the file COPYING, which + * you should have received as part of this distribution. The terms + * are also available at http://curl.haxx.se/docs/copyright.html. + * + * You may opt to use, copy, modify, merge, publish, distribute and/or sell + * copies of the Software, and permit persons to whom the Software is + * furnished to do so, under the terms of the COPYING file. + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY + * KIND, either express or implied. + * + ***************************************************************************/ + +#include "setup.h" + +#ifdef HAVE_SYS_SELECT_H +#include <sys/select.h> +#endif + +#if !defined(HAVE_SELECT) && !defined(HAVE_POLL_FINE) +#error "We can't compile without select() or poll() support." +#endif + +#if defined(__BEOS__) && !defined(__HAIKU__) +/* BeOS has FD_SET defined in socket.h */ +#include <socket.h> +#endif + +#ifdef MSDOS +#include <dos.h> /* delay() */ +#endif + +#include <curl/curl.h> + +#include "urldata.h" +#include "connect.h" +#include "select.h" +#include "warnless.h" + +/* Convenience local macros */ + +#define elapsed_ms (int)curlx_tvdiff(curlx_tvnow(), initial_tv) + +#ifdef CURL_ACKNOWLEDGE_EINTR +#define error_not_EINTR (1) +#else +#define error_not_EINTR (error != EINTR) +#endif + +/* + * Internal function used for waiting a specific amount of ms + * in Curl_socket_ready() and Curl_poll() when no file descriptor + * is provided to wait on, just being used to delay execution. + * WinSock select() and poll() timeout mechanisms need a valid + * socket descriptor in a not null file descriptor set to work. + * Waiting indefinitely with this function is not allowed, a + * zero or negative timeout value will return immediately. + * Timeout resolution, accuracy, as well as maximum supported + * value is system dependent, neither factor is a citical issue + * for the intended use of this function in the library. + * On non-DOS and non-Winsock platforms, when compiled with + * CURL_ACKNOWLEDGE_EINTR defined, EINTR condition is honored + * and function might exit early without awaiting full timeout, + * otherwise EINTR will be ignored and full timeout will elapse. + * + * Return values: + * -1 = system call error, invalid timeout value, or interrupted + * 0 = specified timeout has elapsed + */ +int Curl_wait_ms(int timeout_ms) +{ +#if !defined(MSDOS) && !defined(USE_WINSOCK) +#ifndef HAVE_POLL_FINE + struct timeval pending_tv; +#endif + struct timeval initial_tv; + int pending_ms; + int error; +#endif + int r = 0; + + if(!timeout_ms) + return 0; + if(timeout_ms < 0) { + SET_SOCKERRNO(EINVAL); + return -1; + } +#if defined(MSDOS) + delay(timeout_ms); +#elif defined(USE_WINSOCK) + Sleep(timeout_ms); +#else + pending_ms = timeout_ms; + initial_tv = curlx_tvnow(); + do { +#if defined(HAVE_POLL_FINE) + r = poll(NULL, 0, pending_ms); +#else + pending_tv.tv_sec = pending_ms / 1000; + pending_tv.tv_usec = (pending_ms % 1000) * 1000; + r = select(0, NULL, NULL, NULL, &pending_tv); +#endif /* HAVE_POLL_FINE */ + if(r != -1) + break; + error = SOCKERRNO; + if(error && error_not_EINTR) + break; + pending_ms = timeout_ms - elapsed_ms; + if(pending_ms <= 0) + break; + } while(r == -1); +#endif /* USE_WINSOCK */ + if(r) + r = -1; + return r; +} + +/* + * Wait for read or write events on a set of file descriptors. It uses poll() + * when a fine poll() is available, in order to avoid limits with FD_SETSIZE, + * otherwise select() is used. An error is returned if select() is being used + * and a file descriptor is too large for FD_SETSIZE. + * + * A negative timeout value makes this function wait indefinitely, + * unles no valid file descriptor is given, when this happens the + * negative timeout is ignored and the function times out immediately. + * When compiled with CURL_ACKNOWLEDGE_EINTR defined, EINTR condition + * is honored and function might exit early without awaiting timeout, + * otherwise EINTR will be ignored. + * + * Return values: + * -1 = system call error or fd >= FD_SETSIZE + * 0 = timeout + * [bitmask] = action as described below + * + * CURL_CSELECT_IN - first socket is readable + * CURL_CSELECT_IN2 - second socket is readable + * CURL_CSELECT_OUT - write socket is writable + * CURL_CSELECT_ERR - an error condition occurred + */ +int Curl_socket_check(curl_socket_t readfd0, /* two sockets to read from */ + curl_socket_t readfd1, + curl_socket_t writefd, /* socket to write to */ + long timeout_ms) /* milliseconds to wait */ +{ +#ifdef HAVE_POLL_FINE + struct pollfd pfd[3]; + int num; +#else + struct timeval pending_tv; + struct timeval *ptimeout; + fd_set fds_read; + fd_set fds_write; + fd_set fds_err; + curl_socket_t maxfd; +#endif + struct timeval initial_tv = {0,0}; + int pending_ms = 0; + int error; + int r; + int ret; + + if((readfd0 == CURL_SOCKET_BAD) && (readfd1 == CURL_SOCKET_BAD) && + (writefd == CURL_SOCKET_BAD)) { + /* no sockets, just wait */ + r = Curl_wait_ms((int)timeout_ms); + return r; + } + + /* Avoid initial timestamp, avoid curlx_tvnow() call, when elapsed + time in this function does not need to be measured. This happens + when function is called with a zero timeout or a negative timeout + value indicating a blocking call should be performed. */ + + if(timeout_ms > 0) { + pending_ms = (int)timeout_ms; + initial_tv = curlx_tvnow(); + } + +#ifdef HAVE_POLL_FINE + + num = 0; + if(readfd0 != CURL_SOCKET_BAD) { + pfd[num].fd = readfd0; + pfd[num].events = POLLRDNORM|POLLIN|POLLRDBAND|POLLPRI; + pfd[num].revents = 0; + num++; + } + if(readfd1 != CURL_SOCKET_BAD) { + pfd[num].fd = readfd1; + pfd[num].events = POLLRDNORM|POLLIN|POLLRDBAND|POLLPRI; + pfd[num].revents = 0; + num++; + } + if(writefd != CURL_SOCKET_BAD) { + pfd[num].fd = writefd; + pfd[num].events = POLLWRNORM|POLLOUT; + pfd[num].revents = 0; + num++; + } + + do { + if(timeout_ms < 0) + pending_ms = -1; + else if(!timeout_ms) + pending_ms = 0; + r = poll(pfd, num, pending_ms); + if(r != -1) + break; + error = SOCKERRNO; + if(error && error_not_EINTR) + break; + if(timeout_ms > 0) { + pending_ms = (int)(timeout_ms - elapsed_ms); + if(pending_ms <= 0) { + r = 0; /* Simulate a "call timed out" case */ + break; + } + } + } while(r == -1); + + if(r < 0) + return -1; + if(r == 0) + return 0; + + ret = 0; + num = 0; + if(readfd0 != CURL_SOCKET_BAD) { + if(pfd[num].revents & (POLLRDNORM|POLLIN|POLLERR|POLLHUP)) + ret |= CURL_CSELECT_IN; + if(pfd[num].revents & (POLLRDBAND|POLLPRI|POLLNVAL)) + ret |= CURL_CSELECT_ERR; + num++; + } + if(readfd1 != CURL_SOCKET_BAD) { + if(pfd[num].revents & (POLLRDNORM|POLLIN|POLLERR|POLLHUP)) + ret |= CURL_CSELECT_IN2; + if(pfd[num].revents & (POLLRDBAND|POLLPRI|POLLNVAL)) + ret |= CURL_CSELECT_ERR; + num++; + } + if(writefd != CURL_SOCKET_BAD) { + if(pfd[num].revents & (POLLWRNORM|POLLOUT)) + ret |= CURL_CSELECT_OUT; + if(pfd[num].revents & (POLLERR|POLLHUP|POLLNVAL)) + ret |= CURL_CSELECT_ERR; + } + + return ret; + +#else /* HAVE_POLL_FINE */ + + FD_ZERO(&fds_err); + maxfd = (curl_socket_t)-1; + + FD_ZERO(&fds_read); + if(readfd0 != CURL_SOCKET_BAD) { + VERIFY_SOCK(readfd0); + FD_SET(readfd0, &fds_read); + FD_SET(readfd0, &fds_err); + maxfd = readfd0; + } + if(readfd1 != CURL_SOCKET_BAD) { + VERIFY_SOCK(readfd1); + FD_SET(readfd1, &fds_read); + FD_SET(readfd1, &fds_err); + if(readfd1 > maxfd) + maxfd = readfd1; + } + + FD_ZERO(&fds_write); + if(writefd != CURL_SOCKET_BAD) { + VERIFY_SOCK(writefd); + FD_SET(writefd, &fds_write); + FD_SET(writefd, &fds_err); + if(writefd > maxfd) + maxfd = writefd; + } + + ptimeout = (timeout_ms < 0) ? NULL : &pending_tv; + + do { + if(timeout_ms > 0) { + pending_tv.tv_sec = pending_ms / 1000; + pending_tv.tv_usec = (pending_ms % 1000) * 1000; + } + else if(!timeout_ms) { + pending_tv.tv_sec = 0; + pending_tv.tv_usec = 0; + } + r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout); + if(r != -1) + break; + error = SOCKERRNO; + if(error && error_not_EINTR) + break; + if(timeout_ms > 0) { + pending_ms = timeout_ms - elapsed_ms; + if(pending_ms <= 0) { + r = 0; /* Simulate a "call timed out" case */ + break; + } + } + } while(r == -1); + + if(r < 0) + return -1; + if(r == 0) + return 0; + + ret = 0; + if(readfd0 != CURL_SOCKET_BAD) { + if(FD_ISSET(readfd0, &fds_read)) + ret |= CURL_CSELECT_IN; + if(FD_ISSET(readfd0, &fds_err)) + ret |= CURL_CSELECT_ERR; + } + if(readfd1 != CURL_SOCKET_BAD) { + if(FD_ISSET(readfd1, &fds_read)) + ret |= CURL_CSELECT_IN2; + if(FD_ISSET(readfd1, &fds_err)) + ret |= CURL_CSELECT_ERR; + } + if(writefd != CURL_SOCKET_BAD) { + if(FD_ISSET(writefd, &fds_write)) + ret |= CURL_CSELECT_OUT; + if(FD_ISSET(writefd, &fds_err)) + ret |= CURL_CSELECT_ERR; + } + + return ret; + +#endif /* HAVE_POLL_FINE */ + +} + +/* + * This is a wrapper around poll(). If poll() does not exist, then + * select() is used instead. An error is returned if select() is + * being used and a file descriptor is too large for FD_SETSIZE. + * A negative timeout value makes this function wait indefinitely, + * unles no valid file descriptor is given, when this happens the + * negative timeout is ignored and the function times out immediately. + * When compiled with CURL_ACKNOWLEDGE_EINTR defined, EINTR condition + * is honored and function might exit early without awaiting timeout, + * otherwise EINTR will be ignored. + * + * Return values: + * -1 = system call error or fd >= FD_SETSIZE + * 0 = timeout + * N = number of structures with non zero revent fields + */ +int Curl_poll(struct pollfd ufds[], unsigned int nfds, int timeout_ms) +{ +#ifndef HAVE_POLL_FINE + struct timeval pending_tv; + struct timeval *ptimeout; + fd_set fds_read; + fd_set fds_write; + fd_set fds_err; + curl_socket_t maxfd; +#endif + struct timeval initial_tv = {0,0}; + bool fds_none = TRUE; + unsigned int i; + int pending_ms = 0; + int error; + int r; + + if(ufds) { + for(i = 0; i < nfds; i++) { + if(ufds[i].fd != CURL_SOCKET_BAD) { + fds_none = FALSE; + break; + } + } + } + if(fds_none) { + r = Curl_wait_ms(timeout_ms); + return r; + } + + /* Avoid initial timestamp, avoid curlx_tvnow() call, when elapsed + time in this function does not need to be measured. This happens + when function is called with a zero timeout or a negative timeout + value indicating a blocking call should be performed. */ + + if(timeout_ms > 0) { + pending_ms = timeout_ms; + initial_tv = curlx_tvnow(); + } + +#ifdef HAVE_POLL_FINE + + do { + if(timeout_ms < 0) + pending_ms = -1; + else if(!timeout_ms) + pending_ms = 0; + r = poll(ufds, nfds, pending_ms); + if(r != -1) + break; + error = SOCKERRNO; + if(error && error_not_EINTR) + break; + if(timeout_ms > 0) { + pending_ms = timeout_ms - elapsed_ms; + if(pending_ms <= 0) + break; + } + } while(r == -1); + + if(r < 0) + return -1; + if(r == 0) + return 0; + + for(i = 0; i < nfds; i++) { + if(ufds[i].fd == CURL_SOCKET_BAD) + continue; + if(ufds[i].revents & POLLHUP) + ufds[i].revents |= POLLIN; + if(ufds[i].revents & POLLERR) + ufds[i].revents |= (POLLIN|POLLOUT); + } + +#else /* HAVE_POLL_FINE */ + + FD_ZERO(&fds_read); + FD_ZERO(&fds_write); + FD_ZERO(&fds_err); + maxfd = (curl_socket_t)-1; + + for(i = 0; i < nfds; i++) { + ufds[i].revents = 0; + if(ufds[i].fd == CURL_SOCKET_BAD) + continue; + VERIFY_SOCK(ufds[i].fd); + if(ufds[i].events & (POLLIN|POLLOUT|POLLPRI| + POLLRDNORM|POLLWRNORM|POLLRDBAND)) { + if(ufds[i].fd > maxfd) + maxfd = ufds[i].fd; + if(ufds[i].events & (POLLRDNORM|POLLIN)) + FD_SET(ufds[i].fd, &fds_read); + if(ufds[i].events & (POLLWRNORM|POLLOUT)) + FD_SET(ufds[i].fd, &fds_write); + if(ufds[i].events & (POLLRDBAND|POLLPRI)) + FD_SET(ufds[i].fd, &fds_err); + } + } + + ptimeout = (timeout_ms < 0) ? NULL : &pending_tv; + + do { + if(timeout_ms > 0) { + pending_tv.tv_sec = pending_ms / 1000; + pending_tv.tv_usec = (pending_ms % 1000) * 1000; + } + else if(!timeout_ms) { + pending_tv.tv_sec = 0; + pending_tv.tv_usec = 0; + } + r = select((int)maxfd + 1, &fds_read, &fds_write, &fds_err, ptimeout); + if(r != -1) + break; + error = SOCKERRNO; + if(error && error_not_EINTR) + break; + if(timeout_ms > 0) { + pending_ms = timeout_ms - elapsed_ms; + if(pending_ms <= 0) + break; + } + } while(r == -1); + + if(r < 0) + return -1; + if(r == 0) + return 0; + + r = 0; + for(i = 0; i < nfds; i++) { + ufds[i].revents = 0; + if(ufds[i].fd == CURL_SOCKET_BAD) + continue; + if(FD_ISSET(ufds[i].fd, &fds_read)) + ufds[i].revents |= POLLIN; + if(FD_ISSET(ufds[i].fd, &fds_write)) + ufds[i].revents |= POLLOUT; + if(FD_ISSET(ufds[i].fd, &fds_err)) + ufds[i].revents |= POLLPRI; + if(ufds[i].revents != 0) + r++; + } + +#endif /* HAVE_POLL_FINE */ + + return r; +} + +#ifdef TPF +/* + * This is a replacement for select() on the TPF platform. + * It is used whenever libcurl calls select(). + * The call below to tpf_process_signals() is required because + * TPF's select calls are not signal interruptible. + * + * Return values are the same as select's. + */ +int tpf_select_libcurl(int maxfds, fd_set* reads, fd_set* writes, + fd_set* excepts, struct timeval* tv) +{ + int rc; + + rc = tpf_select_bsd(maxfds, reads, writes, excepts, tv); + tpf_process_signals(); + return(rc); +} +#endif /* TPF */ |